diff --git a/Release/include/cpprest/details/http_client_impl.h b/Release/include/cpprest/details/http_client_impl.h
index 2f88472a50..bb351526a1 100644
--- a/Release/include/cpprest/details/http_client_impl.h
+++ b/Release/include/cpprest/details/http_client_impl.h
@@ -57,6 +57,10 @@ static utility::string_t flatten_http_headers(const http_headers &headers)
     utility::string_t flattened_headers;
     for(auto iter = headers.begin(); iter != headers.end(); ++iter)
     {
+        utility::string_t header_name = iter->first;
+        if (utility::details::str_icmp(header_name, header_names::host)) {
+            continue;
+        }
         flattened_headers.append(iter->first);
         flattened_headers.push_back(':');
         flattened_headers.append(iter->second);
diff --git a/Release/src/http/client/http_client_asio.cpp b/Release/src/http/client/http_client_asio.cpp
index bff2ff4843..694e961976 100644
--- a/Release/src/http/client/http_client_asio.cpp
+++ b/Release/src/http/client/http_client_asio.cpp
@@ -394,14 +394,21 @@ class asio_context : public request_context, public std::enable_shared_from_this
         std::ostream request_stream(&m_body_buf);
         request_stream.imbue(std::locale::classic());
 
-        request_stream << method << " " << encoded_resource << " " << "HTTP/1.1" << CRLF << "Host: " << host;
+        request_stream << method << " " << encoded_resource << " " << "HTTP/1.1" << CRLF;
+        request_stream << "Host: ";
 
         int port = base_uri.port();
         if (base_uri.is_port_default())
         {
             port = (m_connection->is_ssl() ? 443 : 80);
         }
-        request_stream << ":" << port << CRLF;
+
+        std::string specified_host_header;
+        if (m_request.headers().match(header_names::host, specified_host_header)) {
+            request_stream << specified_host_header << CRLF;
+        } else {
+            request_stream << host << ":" << port << CRLF;
+        }
 
         // Extra request headers are constructed here.
         utility::string_t extra_headers;
diff --git a/Release/tests/functional/http/client/header_tests.cpp b/Release/tests/functional/http/client/header_tests.cpp
index 83bee7cab5..697bc8173c 100644
--- a/Release/tests/functional/http/client/header_tests.cpp
+++ b/Release/tests/functional/http/client/header_tests.cpp
@@ -382,6 +382,37 @@ TEST_FIXTURE(uri_address, parsing_content_type_redundantsemicolon_string)
     auto resp = client.request(methods::GET).get();
     VERIFY_ARE_EQUAL(resp.extract_string().get(), utility::conversions::to_string_t(body));
 }
+
+TEST_FIXTURE(uri_address, overwrite_http_header)
+{
+    test_http_server::scoped_server scoped(m_uri);
+    http_client client(m_uri);
+    
+    // Test default case of cpprestsdk setting host header as host:port
+    auto& host = m_uri.host();
+    int port = m_uri.port();
+    utility::string_t expected_default_header = host + ":" + std::to_string(port);
+    http_request default_host_headers_request(methods::GET);
+    scoped.server()->next_request().then([&](test_request *p_request) 
+    {
+        auto headers = p_request->m_headers;
+        VERIFY_ARE_EQUAL(expected_default_header, headers[header_names::host]);
+        p_request->reply(200);
+    });
+
+    client.request(default_host_headers_request).get();
+
+    // Test case where we overwrite the host header
+    http_request overwritten_host_headers_request(methods::GET);
+    overwritten_host_headers_request.headers().add("Host", host);
+    scoped.server()->next_request().then([&](test_request *p_request)
+    {
+        auto headers = p_request->m_headers;
+        VERIFY_ARE_EQUAL(host, headers[header_names::host]);
+        p_request->reply(200);
+    });
+    client.request(overwritten_host_headers_request).get();
+}
 } // SUITE(header_tests)
 
-}}}}
\ No newline at end of file
+}}}}